1. Field of the Invention
The present invention relates to a two-stroke diesel engine.
2. Description of the Related Art
To obtain a good loop scavenging operation in the combustion chamber of a known two-stroke diesel engine, a masking wall is provided for masking the valve opening between the valve seat and the peripheral portion of the intake valve, which is located on the cylinder axis side, and, at the same time, masking the valve opening between the valve seat and the peripheral portion of the exhaust valve, which is located on the cylinder axis side, when the valve lifts of the intake valve and the exhaust valve are small. A fuel injector is arranged on the central portion of the inner wall of the cylinder head to inject fuel directly toward the combustion chamber (U.S. Pat. No. 4,162,662). In this two-stroke diesel engine, air flowing into the combustion chamber from the intake port flows toward the top face of the piston along the inner wall of the cylinder. Subsequently, the flow direction of the air on the top face of the piston is changed, and the air then made to flow toward the exhaust port along the inner wall of the cylinder, to thereby carry out a loop scavenging operation.
As another type of two-stroke diesel engine, a two-stroke diesel engine having a prechamber is known. In this engine, to obtain a good combustion in the prechamber, it is necessary to sufficiently scavenge the interior of the prechamber. In this case, if the loop scavenging operation is carried out, a good scavenging of the main chamber can be obtained. Nevertheless, whether or not a good scavenging operation can be obtained for the prechamber depends on the location of the prechamber, and therefore, if the location of the prechamber is not appropriate, it is difficult to obtain a good scavenging operation of same.